


Orihara Threesome

by tenser



Category: Durarara!!
Genre: Anal Sex, Bisexual, Bisexual Izaya, Blow Jobs, Cunnilingus, Dirty Talk, Fingering, First Time, Incest, Kinkmeme, Manipulation, Multi, Orgasms, Pornography, Smut, Threesome - F/F/M, Twincest, Vaginal Sex, my magnum opus tbh
Language: English
Status: Completed
Published: 2020-07-11
Updated: 2020-07-17
Packaged: 2021-03-05 06:13:33
Rating: Explicit
Warnings: Underage
Chapters: 2
Words: 8,892
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25209763
Author URL: https://archiveofourown.org/users/tenser/pseuds/tenser
Summary: Oriharas are intense and demanding—the younger sisters are just as bad as their older brother. So when Mairu and Kururi Orihara insist that Izaya teach them about sex, they get the hands-on lesson they’ve been pestering him for.
Relationships: Orihara Izaya/Orihara Kururi/Orihara Mairu
Comments: 3
Kudos: 35





	1. Chapter 1

**Author's Note:**

> UNDERAGE! And there’s a bit more buildup than I expected, so keep scrolling for smut. Originally for the kinkmeme: https://drrrkink.livejournal.com/7084.html?thread=26569644

Mairu Orihara knew what it felt like to fall in love.

It happened one night during the last year Izaya still lived with her and Kururi. Despite their absent parents paying all the bills, the Orihara household tended to be dark at night, lit mostly by electronics and media. They had no need to light the common spaces when their world was piped in through TV and computers and games; and the glut of products from those pursuits clotted in stacks in the arteries of the house and gathered in larger piles in the rooms.

The hallway to Izaya’s room in particular was stacked on both sides with books—the heavy kind that Mairu and Kururi puzzled over until Mairu grew bored and fashioned paper airplanes from the pages. Izaya never cared—he wouldn’t put anything outside of his room that he wasn’t okay with being destroyed by his rambunctious little sisters. 

Those stacks of books were what Mairu wove through that fateful night, drawn to the flickering light under Izaya’s door. The twins were supposed to be asleep but she was restless. So after playing around in the bathroom for a while, when she noticed the light, she investigated. It gave her a good excuse to go bother her brother.

Izaya’s door was locked to keep out unwanted sisters. Good thing Mairu had learned to pick the lock long ago! Hairpins could open any door. She and Kururi had wanted to make a copy of the key (since that would be a bigger violation of their brother’s privacy), but he was too good at hiding it.

She pushed the door in with one finger. No resistance, no traps, no motion inside. She gingerly stepped into the room.

Izaya lay passed out on the bed. The pale flickering light of the TV illuminated dark patches on his slack face. The particular patterns and sizes of the dark patches looked like bruises and scrapes. There was even a bit of blood by his mouth. Mairu knew Izaya often got in a lot of trouble because he was a bad person, so he’d probably been attacked by someone who he had pissed off.

As interesting as his injuries were, she cared little for her brother’s well being, and even if she had, all other thoughts washed away once the TV caught her attention.

Love at first sight was the only way to describe the feeling—a deep and vast emotional connection to the imagery. The feeling was so powerful that her breath caught in her chest and she lay riveted to the spot. Nothing had ever been this vibrant in the entire world.

On screen, the luscious world of lesbian pornography unfolded. There were two women, the camera focused so close on their shiny bodies that they were reduced to torsos and glistening pussies, each of which were filled with the other woman’s pumping fingers. Mairu had seen grown women’s breasts before, but they had been the withered and oddly-jutting real-world boobs at the public baths. They might as well have belonged to a different species compared to the overflowing bounty of these ample chests pressed against each other.

The camera hyper-focused on one woman sinking her manicured fingers into the pussy of her willing partner, and Mairu saw the most intimate of human anatomy splayed larger than life in front of her.

The intensity of the visuals, the odd jerking way the figures moved was so foreign and yet Mairu understood the meaning as if sex were a native tongue she’d simply forgotten the words to until that moment.

Transfixed was the only word to describe her state for the next thirty minutes. Only when the screen eventually went blank did awareness of her surroundings come back to her.

She looked back at Izaya, but he lay as dead asleep as before. The blue light of the screen gently played across his beaten face. Mairu stared at him nearly unseeing, images of sex behind her eyes. She kicked the bed, testing her luck, hoping that Izaya would wake up to be in this momentous moment with her.

He didn’t, of course. That was just like Iza-nii, always disappointing and unavailable. As she replayed the DVD, she laid her head against the bed, so close to his, and cherished his presence along with the warm feeling in her chest.

***

Showing Kururi what she’d seen was of the utmost importance. 

After Izaya left for school the next morning, the twins snuck back into the house. But the DVD was nowhere to be found!

“Stupid Iza-nii, “ Mairu pouted. “Why did he take it away?”

“He noticed you?” Kururi asked.

“No way, he was conked out like a dead person,” Mairu said. “He probably took it back to school because he wants to sell it to somebody. It was really amazing! The best thing ever!”

“More?” Kururi asked.

“You think there are more DVDs like that?” It hadn’t dawned on Mairu that there might be more DVDs with similar content. That seemed way too good to be true. But they’d combed through Izaya’s DVDs before and there was nothing like that, so even if other magical DVDs existed, there were none in the house. So they had to suspend their search temporarily.

After school, which they went to only because there was nothing else to do, Mairu impatiently waited for Izaya to come home. The twins never knew when he was going to return, so they were in the custom of making dinner for themselves. Neither was a chef prodigy, so tonight like most nights, it was leftover curry. They’d already cleaned the dishes by the time they heard a key in the front door.

When Izaya limped through the door, Mairu and Kururi rushed him in the hall.

“Iza-nii, buy me a DVD like you had last night!” Mairu shouted.

Izaya blanched, his already drained features turning powder white.

“Kururi needs to see the naked ladies!” Mairu insisted. “Pleeeeeeease!”

“Oh my, my sisters are precocious,” Izaya finally sighed, as he took off his shoes. The twins looked at him with pleading eyes.

“You know, Mairu and Kururi, pornography doesn’t just come on DVDs,” Izaya chided, his earlier shock replaced with typical condescension.

Mairu’s heart leapt. “There’s a word for it?!” That was so awesome. “Pornography! Pornography! Porn~o~gra~phy~!”

“Yes, pornography,” Izaya explained. “The human act of procreation captured in media for entertainment and erotic purposes.”

“Erotic,” Kururi echoed.

“As I said, it’s not just on DVDs,” Izaya continued as he went into the kitchen. He ignored the curry and microwaved a single croquette. He must have been ravenous from his injuries; the twins rarely saw him eat. “Pornography is produced in many forms for a variety of consumption styles. There are DVDs, online video clips, prose books, image collections, magazines, manga—and most of it is available at the convenience store.”

Mairu was practically sweating with excitement, and she pressed up against her brother as he sat down at their table to divide up his croquette with his chopsticks.

“Iza-nii, buy me pornography! C’mon!”

Annoyed, Izaya tried to shake her off. But Kururi joined in, tugging at his sleeve. They were persistent enough that he dug into his wallet and produced a 1,000 yen note. The girls shut up as he presented it.

“Go buy whatever porn you like,” he smirked. “They’ll sell it to you. They’ll never believe you’re getting it for yourself.”

“Yessss!” Mairu shouted, yanking the money from her brother’s hand and brandishing it at the heavens.

“Yay,” added Kururi.

Iza-nii didn’t tell them where to find the pornography at the convenience store, but the sisters were good at finding things. They went to the magazine section, and overflowing swimsuits and improper panty shots leapt out, asking to be bought. But manga wasn’t what Mairu came for. She wanted a movie.

“DVD,” Kururi pointed at a magazine that contained a DVD. The combo pack was shrink-wrapped, but Mairu sliced open the package with her fingernail. The DVD had a naked woman on it, mosaics over her crotch. The combo was exactly 1,000 yen.

When they bought it, they said it was for their big brother.

Soon as they got home, the twins pestered Iza-nii about joining them to watch it.

“Watch it with us, Iza-nii,” Mairu whined.

“You can watch it on your own," Izaya said.

“You’re already on the couch cuz you’re hurt cuz somebody beat you up, so just watch it with us already,” Mairu continued to whine.

Izaya winced, just the reaction Mairu wanted. But Kururi sealed the deal by going and sitting in Izaya’s lap. Mairu jumped up and sat next to them. She grabbed Kururi’s hand. Izaya sighed and started looking at his phone. Mairu didn’t care if he wasn't paying attention. They were all going to watch something mind-blowing together!

The DVD started and it was just a woman in a skimpy outfit posing and gyrating for the camera. That went on for a while, and Mairu started to get nervous. This really wasn’t like the other DVD at all.

Still, Kururi was squeezing her hand, so it wasn’t entirely bad.

The show continued. The woman stripped, and then a man whose face was always hidden got in bed with her and put his penis in her. This part was more interesting and more like what she remembered, but it didn’t have the same spark as watching the two ethereal women. And mosaics blurred out the important parts. After the sex ended, the scene faded to black.

“That wasn’t pornography!” Mairu blurted.

Izaya looked down at his sister, amused. “Oh? Why not?”

“Not erotic,” Kururi interjected.

“How do you know what erotic is? You’re too young to have a sex drive,” Izaya snorted. “Or do you? Did you feel something tingling in your body? Or maybe you imagined something you never thought of before? Tell me, what was it like to see pornography for the first time?”

Mairu cut in, because she had an opinion and was greatly personally invested. “I felt something when I saw the DVD that YOU had, Iza-nii! But this was boring.”

“So then,” Izaya said, lifting Kururi up and setting her down next to her sister. “Did you both learn something? Not all pornography is good, moreover, the taste of the consumer is paramount to the enjoyment of the product. Look around on the internet if you really want to understand what you like. Exposure is the only way to hone your sensibilities. Now excuse me, I have some work to do.”

Mairu thought Izaya was being dismissive. But the next day, he actually did something nice (it was undoubtedly in his own self-interest of watching human reactions) and brought home that first DVD. He left the room, only stopping outside the door to watch their reactions from time to time, saying nothing.

Mairu and Kururi watched the magical DVD, happily transfixed.

***

Mairu loved pornography.

For the next few years, the youngest Orihara collected every scrap of pornography she could get her hands on. The way some kids might collect action figures or glass unicorns or other trinkets, she hoarded dirty magazines, filthy DVDs, indecent games and whatever she could get her hands on. It was her hobby, her passion.

She bothered Izaya about it a lot, sending him texts to ask his opinion about a clip or photo book. He had moved out when he graduated high school, so his phone was the only way to reach him on these crucial matters. He rarely responded, but he didn’t respond to most of their texts anyway so that was normal.

For all its vigor, Mairu’s obsession was platonic at first. It wasn’t until puberty hit that pornography actually did anything for her sexually.

She awoke to pornography’s true powers while watching a new DVD, when her hand drifted to press against her crotch. She ground against the pressure, feeling new sensations. The fabric of her underwear clung to that hot part of her groin in a way that really piqued her interest. She humped her hand more, getting more forceful until orgasm splashed across her brain.

She fell onto her back, completely wiped out. Kururi, who had watched the whole thing, came over and sniffed the peculiar odor of her sister’s crotch.

Overwhelmed with the realization that her life’s purpose was to be the pursuit of erotic pleasure, Mairu could barely spare the thought or energy to lift her hand and run it through her sister’s hair encouragingly. But she did.

Kururi mouthed Mairu’s wet underwear, nuzzling against the hot flesh. Her hair tickled her sister’s thighs, but Mairu was still too overwhelmed to respond.

Kururi put a hand down her own underwear, touching herself in mimicked motion learned from years of porn. She came face-first in Mairu’s crotch.

A golden age of adolescent hormone-driven lust had begun.

***

The Orihara sisters had special details to work out when it came to puberty.

Puberty was building them adult bodies, but there was just one problem—their genetics were the same. Without active manipulation, they’d look the same. But their life philosophy dictated they be complementary opposites.

Some tinkering was called to split their sexual traits evenly.

Mairu became the lewd, forward one and Kururi the shy, embarrassed one. They didn’t have to discuss who got what—Mairu had first dibs having seen porn first. Secretly she knew Kururi was envious—left to her own devices, Kururi would be the more forward and perverted one.

They assigned each other opposing adult costumes: the most fetishistic wear they could sport on a daily basis was a sailor suit and gym clothes, so they went with that. Kururi’s butt looked great popping out the bottom of the gym shorts, so Mairu didn’t complain that she was stuck with the less-revealing sailor suit.

Next came assigning each other physical traits to encompass the opposite poles of porn actresses. AV stars tended to either be busty or to have flat, childlike breasts. Kururi was selected to be busty and curvy, another concession for Mairu being the perverted one.

Mairu began to wear tight bras all the time, and they bought Kururi big bras to fill with padding. Kururi started working out her pectoral muscles to build mass. Beyond that they modified their diet—Kururi ate estrogen-rich and fatty foods and Mairu avoided them. With Izaya sending them a monthly allowance, in addition to their parents’ support, it was possible to maintain two specific and exclusive diets.

But Mairu knew, because she touched Kururi’s boobs every day, that their homegrown boob program wasn’t aggressive enough.

***

“If only these melons were bigger,” Mairu sighed one day, poking her sister’s breasts as they rolled around in bed. Kururi blushed, but Mairu knew that she was thinking the same thing, probably in even ruder terms. Mairu went on, “If you were pregnant, they’d get really big, like cow udders.” _That’s the only way they’ll ever really be different from mine._

“Some guy would have to put his thing in here,” Mairu said, pressing two fingers against the cleft of Kururi’s panties. The older girl jerked away from the touch, so Mairu aggressively curled her fingers until wetness seeped against her fingertips. Knowing that she’d only gotten a poor response because Kururi liked to be fucked not teased, with her other hand, Mairu squeezed Kururi’s tits.

“Wouldn’t you like that, Kuru-nee?” Mairu prattled while turning her sister on nearly effortlessly. “Feel something big and manly inside you. And then he’d come and release all his sperm. I might be a little jealous—” she twisted Kururi’s already reddened and sensitive nipple—“but you could always get rid of the baby after your boobs got bigger.”

Kururi was panting, not paying attention to Mairu’s words at all. Inside her was slick and welcoming, her walls gripping with attentiveness around Mairu’s fingers. She was tensing just the right amount, everything at good angles. Mairu just had to flick her thumb over the head of her sister’s clit to make her come.

After Kururi climaxed and while she came down from her orgasm, Mairu fingered herself. She was the impatient sort, and perfectly capable of getting herself off, so she figured to do just that. Her body was already warm and eager. She came in under a minute, and had perfect technique, but felt a strange capacity to go farther.

Kururi’s hand grazed across her sister’s overheated sex and dipped inside to feel the wetness. Mairu twitched, but nothing was coming from her oversensitive and swollen pussy. But Kururi kept touching. Normally Kururi was a bit standoffish whereas Mairu herself was clingy. Those were the roles they’d assigned to each other. It was nice when the lines blurred. No one had to know, even though maintaining their given identities was the most important thing.

“I want a man,” Kururi whispered.

“Yes,” Mairu said. “Tomorrow let’s find a man to take home and debauch!”

Kururi nodded.

***

A funny thing happened on the way to find a target. Every time they propositioned a random boy on the streets, Mairu would get a weird jealous feeling in her chest, and yank Kururi away at the last second. It was like she couldn’t stand sharing even a fraction of her sister.

“I can’t help it, my heart is reserved for Yuhei,” Mairu lied. Well, only sort-of lied. “No other boy will be as good. What are we going to do?”

“Ask Iza-nii to do us,” Kururi suggested.

Memories of that magical night, THE night, flooded Mairu with a warm, nostalgic feeling. She didn’t really think much of Izaya as a man, but he offered certain safeguards that would bypass her other insecurities. For one, he would understand that Kururi was hers. “Uh-huh,” she agreed.

She called him right up and left a message.

“Iza-nii, we want you to have sex with us,” Mairu said. “Call us soon! Bye!”

As always, Izaya didn’t respond. The girls walked around the streets of Ikebukuro, hoping to run into him as they sometimes did. As they traipsed around, suddenly they saw Shizuo Heiwajima leaning against a park bench.

“Shizu-nii!” called Mairu as she tromped over to Izaya’s mortal enemy. He was relaxed, which meant Izaya hadn’t been around Ikebukuro yet. That in itself was valuable information.

Shizuo was tall and imposing, very manly with the cigarette and formal bartender uniform. Kururi and Mairu glanced at each other. He was a potential target. They had discussed him before—if by discussed, one meant stared at pictures of him, wondered why their brother was so obsessed with him—and imagined how to make him sexy. He’d be extremely hot if only his hair was darker, a little longer and smoother, and if he was a little less tall and lanky.

But he was their brother’s, and so that made him appealing.

“Kururi. Mairu,” Shizuo said. “You lookin’ for Izaya?”

They glomped his arms, putting on their best cute act while also scoping out the feel of his muscled limbs. Mairu gave him a 7 out of 10. Kururi didn’t seem that into him, though. That was too bad because Shizuo probably had a monster dong. She glanced at his pants, but they were very concealing.

“That’s right,” Mairu said. “He’s not answering his phone and we need to talk to him about something.”

Shizuo tsked and made a sour face. What Izaya must like about Shizuo, Mairu mused, was his over-the-top and easy-to-read reactions. Shizuo was clearly pissed at Izaya’s callousness toward his sisters.

“I’ll call him,” Shizuo said. “It’s important right?”

“Yes,” Kururi said, squeezing his arm between her breasts.

Seemingly oblivious to the lewd gesture, Shizuo dialed a number. No one appeared to pick up, then as soon as Shizuo closed his phone, it rang.

“Who is it?” Shizuo gruffed.

“How rude, Shizu-chan, you called me,” Izaya’s flippant tone purred high-pitched through the phone’s speaker. “Or did you butt-dial me while flipping a bus of school children?”

“Shut up, flea. I don’t want to talk to you. You sisters are looking for you.”

“I don’t want to talk to them. I don’t know how to deal with them.”

“They’re right here, so figure it out,” Shizuo said, passing the phone to Mairu.

“Iza-niiiii!” Mairu exclaimed, delighted to be speaking to their target. “Come home! I’ll throw away all your old DVDs if you don’t.”

“I’ve memorized everything valuable from any books or DVDs left at home,” Izaya said. “You can put them in a bonfire if you wish. It might even be interesting.”

“We have new discs from your office,” Mairu said. She hadn’t wanted to play that card, considering how hard-won those files were to attain, but this was worth it.

“That wasn’t very nice of you, but I do have digital file backups,” Izaya chided.

Kururi mouthed something to Mairu. “Shizuo’s coming over to eat dinner!” Mairu repeated.

The line went silent for a moment. Then, “Is he now? Then I better supervise to see that our resident monster doesn’t harm my terrible little sisters.”

“What’d he say?” Shizuo grumbled.

“Yep, he’s coming over, so you better be there to defend our honor, you hear that?” Mairu added.

“Yes, yes,” Izaya sighed, and hung up.

Goal achieved, the girls released Shizuo and bounded off.

“We hope you kill our brother some day!” Mairu shouted cheerfully.

“Huh? Yeah…” Shizuo said, bewildered.


	2. Chapter 2

All three Oriharas knew a bluff when they heard one, so when Izaya opened the door to the family home, he did not expect in the slightest to see Shizuo. He didn’t ask, and the sisters didn’t volunteer an explanation. Kururi came to help him with his black fur-lined jacket. Meanwhile Mairu appraised his body. Their brother was so thin; it seemed he just got slimmer each year. She gave him a 6 out of 10, and that was with a bonus point for dark hair.

“So you want to have sex that badly?” Izaya said.

“Yes, Iza-nii, it has to be you. We’re not ready to be with the man of our dreams yet,” Mairu said.

“High schoolers don’t know their dreams,” Izaya countered. “Although I suppose I knew mine at your age. Anyway, seeing as how you were going to lure in stupid, gullible Shizu-chan if I refused, you didn’t leave me with much choice.”

“We just want to know what it feels like,” Mairu said. “To be with a man. So we can hold out for Yuhei.”

“Teach us,” Kururi insisted.

“Yeah, we know you’re gay but we’re your sisters. You have to,” Mairu said.

Izaya pouted. “I’m as open in my sexuality as you, Mairu. Contrary to whatever you think, I do not lean one way or the other when it comes to my love of humans. Surely you understand that because you feel the same way.”

“I don’t really care,” Mairu said.

Having removed his shoes and jacket, there was nothing left of preamble, and negotiations had been finalized the moment he agreed to come home. Izaya walked up the stairs, Mairu and Kururi following directly behind. In front of their bedroom, he gestured. “In here?” Although Kururi went in, Mairu shook her head. “In your room, Iza-nii.”

The room remained much the same as when he’d left, with the addition of some extra stacks of porn that Mairu had grown bored with.

Izaya looked over his old room and grazed a hand along the spare contents of his closet. Mairu knew every piece contained within, from the high school uniforms to the slinky black dresses. She cheerfully interrupted his meditation.

“Don’t even think about putting the uniform on,” she said. “We don’t want to be with a boy, we want to be with a man. And don’t wear a dress either. Both me and Kururi look better in a skirt than you do so we don’t need that.”

Izaya shot her a cold look. “Perhaps when I was in high school, but I think you’d find I make a much prettier woman now.”

The thought of being with a full-grown woman intrigued and aroused Mairu. She’d fantasized many times about full breasts pillowing around her fingers, and the thick, strong thighs that only adult women had. She gave her skinny brother a quick once-over. “You’re not my type!” she stuck her tongue out.

That got Izaya’s goat. He strode over and pulled his sister into an embrace. He tipped back her head and brought her lips sinfully close. Through a deadly smile, he said, “If you want a man, then I’ll treat you like a man treats a woman. And I’ll have you know that there are many things that women like that I’m quite good at delivering. You simply may melt before you comprehend them. Your interest in achieving maturity may prove you quite immature, and then what will you do?”

Mairu’s breath hitched in her throat. Before she could utter a response, which was dreadfully not forthcoming, Izaya locked lips with her. He pressed his body firmly around hers, arms wrapping across her back and squeezing her shoulders. Her head tilted back with the insistence of his kiss, and she struggled to maintain her balance.

The kiss itself was sensual in a deep, compelling way. She realized she had expected Izaya’s lips to be like Kururi’s, since they were related and decently similar in appearance. But her brother’s lips were stronger, only soft when he wanted them to be, and his mouth was larger.

In other words, everything about the way this was going so far was the sort of exotic and physically overwhelming experience she expected with a man.

As if feeling her calm down, Izaya relinquished the fierce hold, and rested his hands on her hips. His hands felt hot and sinfully controlling, particularly as they pushed up inside her hoodie to caress her sides.

Mairu mewled a little into Izaya’s mouth. He responded by invading with his tongue, melting her further.

Suddenly he pulled away—Kururi was tugging on his sleeve.

“Me too,” she said.

“Of course,” Izaya complied.

Mairu blinked her eyes to watch. Izaya’s hands were still nestled around her, but his long pale neck swiveled to kiss Kururi. As concentrated as she was on her own pleasure, nothing could have distracted her from watching Kururi be kissed. At first, Izaya was chaste, simply smacking her on the lips. But each kiss grew longer, and messier. Soon Kururi’s lips glistened with saliva. Izaya’s lips, though less interesting to look at for Mairu, were kind of pretty and pink, even with the curl of perverse amusement twisting their corners.

Then, suddenly, Mairu was falling, bouncing against the bedsheets. Izaya had pushed her down! And he followed immediately after, caging her against the bed with his body. With a swift motion, he ground his crotch against his sister. To be clear, Izaya was slender but quite strong and had the advantageous position. And although his lean body wasn’t really doing it for her, the tent in his jeans grinding between her legs really, really was.

Letting the pressure of his groin against hers do its work, he returned to kissing. Long deep kisses this time, forcing his tongue to caress the deep recesses of her mouth while giving her little room to reciprocate.

Pinned to the bed by the weight of her older brother, the heat in Mairu’s underwear grew unbearable. The need to feel something inside her ached, and all the little frictions Izaya was causing across her whole body coalesced in a pronounced need in her cunt. If she pretended, she could imagine they were fucking right then—and she did pretend because her brain was fixated on nothing else.

She squeezed his narrow hips between her thighs, drawing him even closer and giving herself more leverage to grind against his erection.

He was going to be inside her so soon. But she already felt like coming.

Sensing how close she was, Izaya ground the fabric of his fly directly against her clit. Mairu gasped as she suddenly came, her brain being washed away by waves of white-hot ecstasy. Her cunt throbbed with pleasure and she dug her fingers into her brother’s back.

Too soon, he withdrew. Without the noticeable erection inside his pants, one might not know he’d just been getting hot and heavy with his sister, the way he crossed his legs and sat back. Mairu panted, her body still jolting with erotic electricity.

“What are you doing now, Iza-nii?” Kururi asked. She stood by the bed, watching it all.

“Surely you don’t expect me to do everything,” Izaya said smugly. “A man who does that in bed is no better than an animal. And anyway, even though it’s not particularly arousing for me since I’ve seen naughty play so many times from you two, the kind of man you seem to be interested in would never pass by the opportunity to watch lesbian foreplay.”

“Understood,” Kururi said.

Despite being in a trough from her orgasm, Mairu knew she had to be the active, forward one because that was her role. She reached out for Kururi, and when her sister complied, drew her down into the bed. She got on top of Kururi.

Mairu thrust her thigh between her sister’s legs and began kissing her. They tasted a foreign tang on their tongues: the taste of their brother. Their bodies pressed against each other in a too-close way, breasts fighting against each other for space and creating delicious pressure.

Struggling for breath and light-headed, Mairu pushed Kururi’s panties down. With practiced hands, she worked at her sister’s cunt, stroking the folds gently.

The bed creaked; another set of fingers softly brushed against hers.

“Iza-nii,” Mairu whined.

“Mairu, be a good girl and help your big brother ready your big sister,” Izaya said.

“Is that dirty talk, Iza-nii?” Mairu chuckled. “Please try harder.”

Izaya scoffed and responded by sliding two fingers along Kururi’s lips until they met at a point to deal the perfect amount of pleasure to her clit. Kururi gasped and shook, her body spasming and her head nuzzling further into the crook of Mairu’s neck. It was a way stronger reaction than anything Mairu had made happen.

“It’s not a good idea to insult your partners,” Izaya laughed. “Please don’t take my level of technique for granted.”

Frustrated by Izaya but also turned on by Kururi’s obvious enjoyment, Mairu bit her lip. She huffed and slipped a finger into the welcoming slick heat of Kururi’s cunt, only to have it pulled away by Izaya.

“Let’s save the penetration for my dick, shall we?” he said. “Isn’t that what you asked for?”

Mairu began to protest, but Kururi herself cut it short by kissing her. Her lips were firm, and her hands firmer when they worked their way to twist Mairu’s nipples. “I want a cock,” Kururi said.

Izaya laughed and continued playing with Kururi’s lips and clit. Kururi began quivering, her cunt clenching as she teetered on the edge of coming. Her body was hot, sweat glistening across her face and smearing on Mairu’s shirt. Mairu could feel her sister’s impending orgasm like it was her own. The need was unbearable.

“Please, Iza-nii,” Mairu begged. “Make Kuru-nee come.”

Kururi was reduced to gasps and needy moans. “Iza-nii…” she whispered.

Her body tensed; Mairu felt the contractions of orgasm from the flesh under her fingertips. She touched her fingers to Izaya’s, which had stilled while pressed lightly against Kururi’s clit. Together they all rode out Kururi’s climax. It had a calming effect on Mairu; not so much on Izaya.

“Humans are so fascinating,” Izaya babbled as he moved away to unzip his pants and shed them. “That sexual behavior would exist so contrary to the proliferation of good genetic progeny, it can only point to the innate bonding qualities that sex facilitates. The two of you exhibit that human quality to its perfection. Should I, being closely genetically related but emotionally distant, have a chance of fitting into this bond?”

“Kuru-nee, can you get up?” Mairu asked, ignoring Izaya’s words, but drawn to his open fly like a moth to flame. Kururi nodded and slid over to the side, clearing Mairu’s view of her brother starting to stroke his cock.

Kururi, noticing, turned her head to watch.

All the incestuous fingering and frotting clearly had affected Izaya, because his dick jutted out stiff and red. His legs were spread quite open, and Mairu took in the white of his thighs and the cute rounds of his tight balls. His shirt was still on, covering the rest of his body in black mystery, but she could see the important parts just fine.

Mairu kind of liked his dick. It wasn’t porn-worthy, considering that like his overall stature, it was on the small side. But his cock had a decent girth. That observation sent a surge of wetness through her cunt.

She scooted forward and observed the member up close. It was firm, mottled with red from the increased blood flow. She marveled as Izaya’s confident hand stroked the shaft, moving the skin up with the tightness of the grip. She noted just how different the texture of the head was, spongy and alien.

His penis smelled musky and erotic. Unable to hold back, she flicked her tongue against the head, and was rewarded with a sharp intake of breath from her brother. She decided right then and there.

“We’re going to suck you off, Iza-nii,” Mairu declared. “We know you have to recover or something afterward, but don’t think you’re getting off the hook. You still have to stay around and fuck us.”

“Ha…” Izaya laughed bitterly, though he mostly panted. “That scenario sounds very pornographic. Is porn where you get all of your ideas from?”

“We’re just thinking of the woman’s pleasure,” Mairu said. “Don’t think that everything ends when the man comes. That’s chauvinistic, Iza-nii.”

“Is it now? Interesting, I doubt you learned that progressiveness from run-of-the-mill porn,” Izaya said.

Anything more he might have said was cut off with a low moan. Mairu was quite serious about making her brother come from a blowjob, and had a massive arsenal of porn-gleaned techniques waiting to be employed for the first time.

“There, like that,” Izaya moaned, when she settled her mouth over the tip. She explored the texture with her tongue, running circles over the glans and tasting the salt slick of fluid welling up from the slit. The cock jumped in her hands as she continued to eagerly mouth its head. “That’s admirable for a first attempt,” Izaya praised.

There was a creak of the bed before her sister’s familiar hands brushed against hers while running up the same shaft. Kururi satisfied herself with just a few exploratory touches before latching her mouth onto her brother’s length.

Izaya sighed in approval.

Mairu welcomed Kururi to join her teasing the head of Izaya’s cock. It was just as filthy as she hoped to have two girls blowing the same cock. The taste of the dick, the saliva lewdy dripping down its length and Kururi’s face right there to kiss… The only thing that made it better was Izaya’s hands coming down on their heads to roughly guide them to take more of his cock.

Mairu slid the head back into her throat, slurping at the pulsing vein along the shaft. It was thick and heavy in her mouth, and the harder she sucked, the thicker it got. Then, unexpectedly, his cock twitched in her mouth.

“Kuru--!” Izaya exclaimed, before whimpering.

Mairu’s eyes flickered open to see what the disturbance was.

Kururi had licked a finger and reached behind Izaya’s balls.

The older twin ground into their brother’s ass insistently, making Izaya much more vocal than he’d been. The sounds smoldered in Mairu’s ears, sending surges of arousal into her cunt. Kururi being so forward and Izaya being so responsive pressed her buttons hard. It took everything she had not to mount her brother’s dick right then.

The twins fell into a blistering rhythm of sucking and fingering that made Izaya quake, his skinny thighs quivering, and moans tearing endlessly from his throat. Mairu felt her brother go impossibly hard against her tongue and then suddenly her mouth was flooded with a salty substance.

She pulled away to let Kururi drink their brother’s come, but she was too slow and the last bursts of Izaya’s semen merely splattered against Kururi’s lips.

Despite the come-sharing failure, the blowjob experiment was a total success. Izaya undone was a sight to behold. Unable to support himself, he fell back against the wall, limbs limp and legs wantonly spread open. His narrow chest heaved and his half-lidded gaze focused on some inner pleasure. A sheen of sweat covered his abdomen and thighs. His cock slowly retreated into itself, a process that fascinated Mairu.

Kururi, less bewitched, licked drops of come from her brother. When she finished, she kissed Izaya on the lips. Mairu watched the shock and then amusement of her brother tasting his own come.

“C’mon, I bet that wasn’t your first time tasting come, right, Iza-nii,” Mairu prodded. “Do you eat Shizuo’s come? Does it all taste the same? Is yours any different? Yours tastes like shiokara by the way.”

Izaya sighed, stretching his taxed body. “Enough. I’m taking a shower.”

“Come back soon,” Kururi said.

***

Mairu was pretty sure Izaya wouldn’t welch on his promise to fuck them, but just in case, they watched under the bathroom door as he showered. To be extra sure, they reached into the bathroom and grabbed his clothes so he wouldn’t be tempted to slip out the window before they could stop him.

She was aching with arousal, still turned on by the whole blowjob thing.

“How long do you think it takes for a guy to get hard again?” she babbled at her sister. “An hour? Is it twenty minutes? Five minutes? Fifteen minutes?”

“Quiet,” Kururi said.

“It’s a half hour, isn’t it? Iza-nii’s been in the shower for like twenty minutes so—”

Kururi’s delicate fingers, so like their brother’s, pressed against Mairu’s lips, silencing her. Far from being quelled, Mairu grinned mischievously and licked at the fingertips, then sucked them into her mouth.

Kururi, not to be outdone, withdrew her fingers and then repositioned them over her groin to mimic a cock.

“Heh,” Mairu chuckled. This was a game she would gladly play. Settling herself between her sister’s thighs, she licked and sucked on her sister’s fingers as if they were a dick. Kururi, mimicking Izaya’s action from earlier, tugged on the back of Mairu’s head until she was face-first in her sister’s panties.

The crisp, wet aroma was deliciously enticing, and Mairu mouthed the damp undergarments until they were sopping with her saliva and her sister’s juices. Kururi trembled, resting against the wall just like Izaya had. Mairu proudly began to think that she had a real talent for oral sex.

Just then, the shower turned off. Before Mairu could bounce off to plaster herself to her brother, Kururi aimed to finish; she ground Mairu’s nose into her clit until waves of orgasm washed through her. Mairu was thoroughly distracted by this, enough so that she didn’t notice Izaya until his shadow fell over them.

With his flat chest bare and a towel strung about his waist, Izaya looked more manly than usual. He looked actually desirable. As far as ratings were concerned in Mairu’s sorely aroused state, he was a 10 out of 10.

“Hmf,” he smirked, then padded to his room.

“Iza-niiii,” Mairu called, rushing after him. Kururi followed after at her own pace.

Before he could put his clothes on, Mairu jumped on his lap and started rubbing against him. Her brother’s shower-heated body, with all its lean angular edges, felt like relief to grind her tortured cunt against.

“Pleeease, Iza-nii,” she begged. “Now.”

“Tell me,” he wound a hand into her hair and whispered in her ear. “How do you think it will be like to lose your virginity?”

“I’m not a virgin, Iza-nii,” Mairu argued, as she found the bulge of Izaya’s cock to rub against.

“Ah, yes, you’re quite experienced with your sister,” Izaya said. “Then tell me, what do you think a cock will feel like inside you?”

“Good,” Kururi answered, her answer complete in its curtness in a way Mairu couldn’t have matched even with her extensive linguistic skills.

“I have a proposition,” Izaya said, leaning back and nudging Mairu away. She refused to budge. “Since the two of you have split every trait between the two of you, which one of you will lose this precious virginity?”

“That’s not fair!” Mairu exclaimed. “You have to have sex with us both!”

“Surely I can have something on my terms,” Izaya said. “After all, I’m being generous with the use of my body as it is. One person will lose their virginity, that is, my cock inside their womb.”

The sisters glanced at each other.

“Mairu."  
“Kuru-nee.” They said in unison.

“How selfless,” Izaya shrugged. “However, if you can’t pick one—“

“Kuru-nee,” Mairu insisted. “It’ll be like pornography to watch her, and I love pornography. Do it, Kuru-nee, I’ll watch.”

Izaya flashed a knowing smile, and that pissed Mairu off because it meant he saw through their act. If they were staying in character, Mairu should have insisted on herself while Kururi either watched quietly or tossed her little sister aside. Mairu wasn’t supposed to be selfless.

“I suppose that’s good enough,” he sighed, beckoning at the silent girl standing across the room.

Mairu’s personal pornographic show began.

The younger twin watched transfixed as Kururi lay down on the bed and Izaya climbed on top of her. Kururi was still mostly clothed while Izaya was naked. Although Mairu meant to watch his dick intently for signs of arousal, she instead was distracted by his nimble fingers working over Kururi’s body, swiftly disrobing her of her clothing. When he went to flip her shirt over her bra, the quiet girl held a hand over her breasts.

Mairu understood. The secret of Kururi’s real breast size was too intimate to disclose to anyone, even Izaya.

Fortunately, he didn’t press, and instead stripped away only her hoodie, then fondled the beautiful bountiful mounds of breasts above her shirt. Mairu could hardly contain herself, already flicking at her own clit at the dirty sight.

It really was just like a private porn shoot.

Izaya pulled down Kururi’s damp panties, and Kururi spread her legs. Mairu’s gaze flashed to her brother’s groin. His dick looked stiff-ish. Not really as good as porn, but she could smell it, and she could see so much more of the scene than in porn. It worked.

Kururi seemed conscious of her role as the porn actress, and true to her demure nature, restrained herself to being the object of touch. It wasn’t Mairu’s favorite version of her sister, but—

Oh. Izaya sat up, lining his cock up with Kururi’s hole. Jealousy reared its ugly head.

“Stop, Iza-nii!” Mairu said. “You don’t have any weird diseases from whoring around, do you? If you do, you can’t put your penis inside.”

“You have a low opinion of me, don’t you?” Izaya said. “I assure you I am perfectly clean. And this is a strange time to ask, isn’t it? If you really cared you would have asked earlier. Are you jealous, Mairu?”

Mairu pouted.

“Please,” Kururi said. “Now.”

Izaya kissed his sister, pressing their bodies close. Mairu’s view of his cock became obscured by Kururi’s thighs. Mairu, heart flip-flopping around between lust, admiration and jealousy, drunk in every detail: Kururi’s tensing legs, her flushed face, the lewd and welcoming cant of her hips.

With a groan, Izaya slipped the head of his cock inside his sister. Kururi gave a soft, high sigh, and Izaya pushed in further. Her legs curled around his back; her hands clawed his shoulders. She gasped as he sank fully into her.

Mairu ached to know what it felt like. She started fingering herself in sympathetic response. Her fingers pressed at her sensitive spots, drawing out blistering arousal, but even so she wanted Izaya’s dick instead. She also wanted to be the one drawing those eerie high-pitched soft noises from her usually silent sister.

Mairu stared at the point where her siblings’ bodies joined. She caught glimpses of her brother’s cock during its slide in and out of her sister’s pussy. His cock was wet with Kururi’s fluids, and flushed darkly with arousal. The same wetness and flush colored Kururi’s inner lips. Mairu marveled at the taut stretch of her sister’s entrance around their brother’s cock. It looked like such a snug fit.

Kururi and Izaya were copulating right next to her, and all she could do was listen to their hot breathing, and feel the tension in Kururi’s body as her older sister accepted Izaya’s cock into her heat. Mad with lust, Mairu couldn’t help finally inserting herself into the scene. She lay down on her back, right next to her sister, mirroring her pose. One hand she linked with her sister’s. The other frantically dug into her own pussy, matching Izaya’s rhythm.

Mairu wanted to be fucked so, so badly.

Suddenly, fingers pressed against her. She hadn’t even realized her eyes had slid shut in concentration until they flickered open to see Izaya reaching a hand between her legs. But instead of sliding into her cunt like she wanted, his fingers circled the soft pucker of her rear entrance.

“Stupid Iza-nii!” Mairu gasped, throwing her head back in confused pleasure.

A finger, slick with lube, slid into her. Being far more vocal than her sister, Mairu cried out in surprise. The blazing fire of her arousal abated as it redirected to accept pleasure from her asshole.

The feeling was strange and invasive. Intimate in just the way she had wanted from sex yet so different from the warm, powerful feelings of her vagina. Two fingers spread her hole, and she let them slide knuckle deep inside the strange space. She felt smooth and wanton, aware of sexual touch in a place that wasn’t supposed to be sexualized.

“Iza-nii, it feels so good,” she said. “Please more!”

“Harder,” echoed Kururi.

“It’s amazing what the human body can be wired to crave,” Izaya laughed as he complied, delivering more powerful thrusts to both his sisters. He slipped a third finger in Mairu, making her feel so filled she was in ecstasy. Her cunt, now morbidly intrigued, throbbed sympathetically.

“Fuck me, Iza-nii,” Mairu called out. “Fuck me, fuck me.”

“Fuck me,” Kururi said.

Suddenly the fingers were gone.

“Don’t stop!” Mairu said. “It feels the best, Iza-nii!”

“Raise your hips,” Izaya said, his voice gone huskier than she’d ever heard. Mairu complied, and was rewarded with the press of something much thicker and heavier than fingers against her quivering hole.

She suddenly realized he meant to fuck her ass.

Before the thrill could even pass, Izaya pressed in, and Mairu shrieked. It hurt more than expected, and she collapsed onto her elbows. And yet, Izaya’s cock filled her whole being, throbbing through her, touching off points of electricity in her tits, her cunt, and as far as her fingertips.

“I hope you appreciate,” Izaya said through labored breaths, “that I’m giving you this particular form of virginity of mine in attempting to comply with the strange habit between you two of splitting experiences.”

Mairu moaned. “You mean you always take it from Shizuo?”

That earned her a thrust that filled her so completely that she lost consciousness for a second.

“What I mean is that when it comes to women, this particular act has never come up before,” Izaya said.

“Feels good,” Kururi spoke for everyone.

Mairu felt her body squeezing around the intrusion, helpless to remove it. Izaya could do whatever he wanted. And she didn’t even care as long as he kept delivering the delicious pressure. He thrust into her evenly and smoothly, and the rhythm built up a warmth that spread to her pussy.

Unable to restrain herself, Mairu ground her forefinger against her clit, providing the spark she needed to inflame her pleasure into a raging crescendo. With a wracking shudder, she climaxed around her brother’s dick, feeling it intensely long and dominating inside her. She surrendered to the pleasure it gave her, and to the sharp necessity of the nub crushed against her finger.

As she came, the world fell away. The orgasm was powerful, blinding, and it submerged her in pleasure. The world moved slow and out of focus. As she drifted back into reality, the hand pressing her against the bed lifted. The presence in her ass presently became as unnatural and annoying as it should have been from the start.

She winced. “Take it out, Iza-nii.”

He did, and she heard him shuffling around. “Did you come in me, Iza-nii?” Mairu said lazily. Hopefully.

“I’m afraid you didn’t really last long enough for that, dear sister,” Izaya smirked.

“Me,” Kururi said, volunteering herself.

“Don’t worry,” Mairu said. “Kuru-nee takes birth control pills” _to make her boobs bigger_ “so you can come a lot inside her.”

Kururi nodded. “Safe.”

“Ahh~” Izaya whined. “You two are terrible. Unfortunately I don’t believe you.”

The snap of a condom. Where had those even been?

“Hurry,” Kururi said.

Ass twitching and brain floating, Mairu drifted towards her sister’s body, which was heated with still-unquenched passion. Mairu wanted to live in that heat, and pressed herself against all the places that Izaya wasn’t already.

Izaya slid back inside his little sister, making Kururi’s body shudder in pleasure. Mairu wanted to ride out the pleasure with Kururi until the end. She twisted her sister’s nipples and kissed her. In homage to the porn they’d watched together all those years ago, she slid their breasts together, as their holes remained open for use.

Kururi gave in first, her fine eyebrows raised high in ecstasy as she shuddered and came around her brother’s cock. Mairu hungrily felt every contraction of her pussy from outside. The flush on Kururi’s cheeks was strong, and Mairu licked at the droplets of sweat welling up across flushed skin.

Just one thing remained the same as pornography—the scene wasn’t going to be over until the man came.

“Iza-nii, you have to come,” Mairu said. “If you don’t, I’ll tell everyone that you fucked your sisters because you’re a sex criminal.”

“Your pillow talk…” Izaya grimaced through labored breaths, “needs…some work.”

Then, unexpectedly, Izaya’s hand was back, playing with her pussy. His movements were sloppy but insistent, from which she deducted the surprising fact that her gay brother actually got something from women’s vaginas and was just fingering her because it turned him on. It made her incredibly happy inside.

She smiled as Izaya grasped her hip and also stuffed Kururi to the hilt. With a few rough jerks that stretched her cunt to its limit, she knew he was coming.

When he pulled out, he pulled off the condom to let hot semen leak onto his sister’s well-used vagina, though no one had the presence of mind for comeplay this time. The white fluid leaked out onto the bed unabated.

***

Kururi was the first to sit up. On each side of her was a collapsed sibling, drowsing in and out of consciousness.

She caressed Mairu’s arm. Her annoying sister had gotten them into something pretty interesting. She could put up with her today.

She gently touched Izaya’s cheek. She’d liked the feeling of his cock in her. Her unavailable brother had been intimate today. She poked his cheek.

He blinked bleary eyes.

“Shower?” she said.

He rose, and stretched like a cat. “Yes, and then I’ll leave. Say goodnight to your sister for me.”

She nodded.

At that moment, the doorbell rang.

Izaya tensed, hastily racing for his clothes. Not one for nonsense, Kururi straightened her top, put on a skirt, wiped her thighs with a sock, and then padded downstairs. A certain blond bartender carrying a box of chocolates waited at the door.

Before she could open the door, Izaya pushed past her to look through the peephole. He giggled, a loud maniacal thing that sounded foreign to her ears.

“Ah, Shizu-chan actually came? He’s so gullible!”

“Flea?” the superhuman’s ears picked up the familiar cackle.

Kururi opened the door. Izaya dashed out, underneath the range of Shizuo’s arms and ran off into the night. To the eyes of a martial artist, and also the person who knew what Ikebukuro’s premier informant had just been up to, his gait appeared weak and slow.

The big blond gave the box of chocolates to Kururi. “Sorry. He’s up to somethin’! He smells funny,” Shizuo offered as an excuse and tore off after his quarry.

“Bye,” Kururi said as she looked at the box. It had an indent of a hand.

“What? What?” Mairu popped up in the entryway. “Shizuo actually came for dinner? He’s so gullible! And he left chocolates?”

“Iza-nii left,” Kururi explained.

“That’s okay,” Mairu said, popping a chocolate in her mouth and grinning. “Chocolates are an aphrodisiac, and the night is young! Who needs a dumb brother anyway?”


End file.
